High voltage electrical connection for a display screen

ABSTRACT

A high voltage electrical connection between a base unit and a panel display in a portable computer wherein the base unit and the panel display are pivotably secured to each other about a hinge axis, includes a flexible high voltage electrical conductor extending from the base unit to the panel display. A portion of the electrical conductor extends along the hinge axis such that pivoting of the panel display relative to the base unit causes said portion of the flexible conductor to twist about the hinge axis rather than actively bend.

This application is a Continuation of application Ser. No. 09/146,869filed on Sep. 3, 1998.

BACKGROUND

Most notebook computers include a base unit which houses the processorand keyboard of the computer. A top cover which houses a display screenis pivotably secured to the base unit. Low voltage signals forcontrolling the display screen are provided from the base unit to thedisplay screen by a thin planar flex circuit extending therebetween. Theportion of the planar surface of the flex circuit which crosses thehinge axis of the notebook computer actively bends when the top coveropens or closes. The flex circuit has a very thin cross section and ismade of material flexible enough to allow the flex circuit to withstandtens of thousands of bending cycles without breaking.

The display screen is commonly backlit to improve viewing. Thebacklighting is typically powered by a high voltage inverter locatedwithin the top cover adjacent to the display screen. The high voltageinverter is enclosed within the top cover because the wires required forcarrying high voltage power (about 1500 volts) have a much thicker crosssection than a flex circuit making the high voltage wires less flexibleand unable to withstand repeated bending cycles. Housing the inverter inthe base unit would require the high voltage wires to extend across thehinge axis from the base unit to the display screen, subjecting the highvoltage wires to breakage under the repeated bending and exposing theuser to the possibility of 1500 volts of high voltage electrical shock.

A drawback of positioning the inverter in the top cover adjacent to thedisplay screen is that the display screen must be smaller than the topcover by at least an amount equal to the width of the inverter. Thedisplay screen can be made larger, by locating the inverter behind thedisplay screen. However, this would increase the thickness of the topcover in order to accommodate the inverter, and would in turn increasethe overall thickness of the notebook computer.

SUMMARY OF THE INVENTION

The present invention is directed to a high voltage electricalconnection between a base unit and a panel display in a portablecomputer wherein the base unit and the panel display are pivotablysecured to each other about a hinge axis. The electrical connectionincludes a flexible high voltage electrical conductor extending from thebase unit to the panel display. A portion of the electrical conductorextends along the hinge axis such that pivoting of the panel displayrelative to the base unit causes said portion of the flexible conductorto twist about the hinge axis rather than actively bend. Twisting alength of flexible conductor about its longitudinal axis exerts lessstress on the flexible conductor than if the flexible conductor isrepeatedly bent across its longitudinal axis.

In preferred embodiments, the flexible electrical conductor includes twoinsulated copper braided wires positioned longitudinally adjacent toeach other. A sleeve surrounds a portion of the flexible conductor. Thesleeve is made of a braided material capable of being shrink fitted overthe flexible conductor and prevents wear of the flexible conductor dueto twisting of the flexible conductor against components of thecomputer. Each wire preferably includes 19 twisted tinned annealedcopper wire strands about 0.127 mm in diameter which are covered by apolymeric insulation jacket.

The present invention provides an electrical connection which allows thehigh voltage inverter of a notebook computer to be located in the baseunit while at the same time, eliminating the possibility of conductorbreakage and high voltage electrical shock to the user. As a result, thesize of the display screen can be maximized without increasing thedimensions of the top cover.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects, features and advantages of theinvention will be apparent from the following more particulardescription of preferred embodiments of the invention, as illustrated inthe accompanying drawings in which like reference characters refer tothe same parts throughout the different views. The drawings are notnecessarily to scale, emphasis instead being placed upon illustratingthe principles of the invention.

FIG. 1 is an exploded perspective view of a notebook computer includingthe present invention high voltage electrical connection with thekeyboard and portions of the base unit housing removed.

FIG. 2 is an enlarged perspective view depicting the manner in which thehigh voltage electrical conductor is electrically connected to the highvoltage inverter in the base unit of the notebook computer of FIG. 1.

FIG. 3 is an exploded perspective view of the top cover of the notebookcomputer of FIG. 1, depicting the manner in which the high voltageelectrical conductor is electrically connected to the display screen.

FIG. 4 is an enlarged perspective view of the present inventionelectrical conductor extending from the base unit to the top cover ofthe notebook computer of FIG. 1.

FIG. 5 is a side view of one wire of the high voltage electricalconductor of the computer of FIG. 1 with portions of the wire beingremoved.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 1-4, notebook computer 10 includes a base unit 12 anda top cover 14 which are pivotably secured to each other by a pair ofhinges 18 (FIG. 3) along a hinge axis X. The base unit 12 houses thekeyboard (not shown), processor, drives etc. of the computer 10. The topcover 14 supports the panel display 16 of computer 10. Low voltage datasignals to panel display 16 for controlling panel display 16 areprovided by a conventional flex circuit extending between base unit 12and top cover 14. High voltage power (about 1500 volts) from a highvoltage inverter 56 (FIG. 2) within base unit 12 is provided to paneldisplay 16 by the present invention high voltage connection whichincludes a flexible high voltage conductor 26 extending between inverter56 and panel display 16. The high voltage power is used to backlight thepanel display 16 using techniques in the art.

Top cover 14 includes an outer cover 14 b which supports panel display16 and an inner frame member 14 a which secures panel display 16 toouter cover 14 b (FIG. 3). Inner frame member 14 a and outer cover 14 binclude two respective inner 24 a and outer 24 b hinge cover halveswhich when joined together, form two hinge covers 24. Two hinges 18 arespaced apart from each and enclosed within the interiors 44 (FIG. 4) ofrespective hinge covers 24. Each hinge 18 includes a hinge body 18 bmounted to outer cover 14 b and a hinge mount 18 a which is pivotablysecured to hinge body 18 b (FIG. 3). Each hinge mount 18 a extends fromthe outer axial end of a hinge cover 24 and is secured by screws to abase mount 20 at the rear of base unit 12, thereby pivotably securingtop cover 14 to base unit 12 along hinge axis X (FIG. 1).

As shown in FIG. 2, high voltage conductor 26 includes two insulatedbraided wires 30 and 32 positioned side-by-side. A flexible braidedsleeve 28, preferably about 1 inch wide, is shrink fitted over wires 32and 30 on the portion of conductor 26 near base unit 12 (FIG. 4). Ifdesired, a longer sleeve 28 can be employed. The lower end of wires30/32 are electrically connected to a lower snap fit connector 26 awhich mates with inverter connector 34 (FIG. 2). The upper end of wires30/32 are electrically connected to an upper snap fit connector 26 bwhich mates with panel display connector 38 a (FIG. 3). The snapfittings facilitate the assembly process. Conductor 26 extends upwardlyfrom inverter connector 34 through an opening 46 in base unit housing 12a (FIG. 4). Conductor 26 is then bent at about 90° such that conductor26 enters the right hinge cover 24 of top cover 14 through an opening 40and lies within the interior 44 of hinge cover 24. The portion ofconductor 26 wrapped in sleeve 28 (about one inch) extends from opening46 in base unit housing 12 a into opening 40 of hinge cover 24. Thelongitudinal axis of about a one inch length of conductor 26 liesapproximately along the hinge axis X of notebook computer 10. Conductor26 is then bent again at about 90° to exit the interior 44 of hingecover 24 and enter an opening 42 within outer cover 14 b below displayscreen 16 to couple with panel display connector 38 a (FIG. 3). Paneldisplay connector 38 a is electrically connected to panel display 16 bywires 38.

Top cover 14 is typically rotated about the hinge axis X approximately135° when opened or closed. Such a range of motion would normallyfatigue and break prior art high voltage wires if such wires wereextended between top cover 14 and base unit 12 in a perpendicularrelation to hinge axis X. The reason for this is that the same area ofthe wires are repeatedly bent approximately 135° whenever the top cover14 is opened and closed. Bending wires at the same area exertsalternating stresses to that area which fatigues and breaks the wires.

In contrast, in the present invention, by positioning a length ofconductor 26 along the hinge axis X of notebook computer 10, no activebending of conductor 26 occurs. Although the portions of conductor 26which enter and exit hinge cover 24 are initially bent at approximatelyright angles during assembly, no further bending occurs during use. Theonly cyclic or repeated movement of conductor 26 which occurs during useis that the length of conductor 26 longitudinally lying along hinge axisX twists back and forth approximately 135° about hinge axis X asindicated by the arrow “A” (FIG. 4) when top cover 14 is pivoted open orclosed. The braided sleeve 28 prevents the insulation 48 (FIG. 5) ofwires 30/32 from rubbing against hinge cover 24 and base unit housing 12a when conductor 26 twists, so that the insulation 48 does not wear off.The twisting of conductor 26 occurs along the length of conductor 26between about points 22 and 36 (FIG. 4). This distributes thealternating stresses on conductor 26 over about a one inch length ofconductor 26 instead of at a single spot. This is a large enough area toprevent the conductor 26 from fatiguing. In fact, conductor 26 hassurvived tests of 20,000 cycles of opening and closing top cover 14.

The construction of wire 30 of conductor 26 is depicted in FIG. 5. Wire32 (FIGS. 2-4) is similarly constructed. Wire 30 has an inner bundle 54of seven wire strands 50 twisted around each other. The inner bundle 54is surrounded by an outer series or bundle 52 of 12 wire strands 50which are in turn twisted around inner bundle 54. An outer polymericinsulation covering 48 surrounds the outer series 52 of wire strands 50.The diameter of wire strands 50 is about 0.127 mm with the diameter ofthe entire conductor being about 0.64 mm. Wire strands 50 are preferablymade of tinned annealed copper wire which has a temperature rating ofabout 105° C. Wire 30 has a voltage rating of about 3 KvDC and a maximumresistence of about 91.3 Ohm/Km at 20° C. Insulation 48 is preferably ofdouble thickness and is about 0.48 mm thick with a diameter of about 1.6mm+/−0.15 mm. Insulation 48 has a minimum resistance of about 1000 MOhm/Km at 20° C. and a minimum tensile strength of about 1.06 Kg/mm².Although the preferred number and diameter of wire strands 50 has beendescribed above, the number and diameter of the wire strands can bevaried slightly while still providing desirable mechanical properties.

The length of conductor 26 is preferably about 5½ inches long but,alternatively, can be longer or shorter depending upon the location ofinverter connector 34 or panel display connector 38 a. In addition,connectors 26 a/26 b are preferably made of plastic but alternativelycan be metallic. Although wires 30 and 32 are depicted to be separatewires, alternatively, wires 30 and 32 can be molded to be side by side.

Equivalents

While this invention has been particularly shown and described withreferences to preferred embodiments thereof, it will be understood bythose skilled in the art that various changes in form and details may bemade therein without departing from the spirit and scope of theinvention as defined by the appended claims. Those skilled in the artwill recognize or be able to ascertain using no more than routineexperimentation, many equivalents to the specific embodiments of theinvention described specifically herein. Such equivalents are intendedto be encompassed in the scope of the claims.

For example, connectors 26 a, 26 b, 34 and 38 a can be omitted. In sucha case, the wires 30/32 would be connected directly to inverter 56 andpanel display 16.

What is claimed is:
 1. A computer system, comprising: a panel display; ahousing configured to support a plurality of computing componentscomprising a high voltage inverter for the panel display; a hingestructure rotatably coupled to the panel display and the housing aboutan axis; and a high voltage cable electrically coupled to the highvoltage inverter and the panel display, the high voltage cablecomprising: a twistable portion extending through the hinge structureand along the axis for a desired stress dissipation length.
 2. Thecomputer system of claim 1, wherein the twistable portion is configuredto spread rotational motion of the panel display over the desired stressdissipation length.
 3. The computer system of claim 2, wherein thedesired stress dissipation length is configured to reduce fatigueassociated with the rotational motion.
 4. The computer system of claim1, wherein the high voltage cable comprises a twistably flexibleassembly of conductors and insulative material.
 5. The computer systemof claim 4, wherein the conductors comprise copper.
 6. The computersystem of claim 4, wherein the twistably flexible assembly comprises aprotective external sleeve configured to reduce frictional wear.
 7. Thecomputer system of claim 1, wherein the high voltage cable comprises acurved portion adjacent the twistable portion, the curved portion havinga curve radius configured to facilitate twisting rather than bending ofthe high voltage cable.
 8. A wiring system for a computing devicecomprising a display rotatably coupled to a housing, comprising: a hingestructure having a rotational axis; and a high voltage cable for thedisplay, comprising: a straight portion extending through the hingestructure for a desired length along the rotational axis; and a curvedportion adjacent the straight portion, wherein the curved potioncomprises a gradual curvature.
 9. The wiring system of claim 8, whereinthe straight portion is twistable over the desired length.
 10. Thewiring system of claim 9, wherein the desired length is configured toreduce fatigue of the high voltage cable associated with rotationalmotion of the display about the housing.
 11. The wiring system of claim8, wherein the high voltage cable comprises a twistably flexibleassembly of conductors and insulative material.
 12. The wiring system ofclaim 11, wherein the twistably flexible assembly comprises a protectiveexternal sleeve.
 13. The wiring system of claim 8, wherein the highvoltage cable comprises the curved portion adjacent opposite ends of thestraight portion.
 14. The wiring system of claim 8, wherein the gradualcurvature is configured to facilitate twisting rather than bending ofthe high voltage cable with rotational motion of the display about thehousing.
 15. A method for reducing fatigue in a high voltage electricalconductor between a portable computer housing and a rotatable display,comprising: twistably extending a portion of the high voltage electricalconductor for a desired fatigue dissipation length along a rotationalaxis between the portable computer housing and the rotatable display;and routing adjacent portions of the high voltage electrical conductorinto the computer housing and the rotatable display.
 16. The method ofclaim 15, wherein twistably extending the portion comprises preventinglocalized stresses in the high voltage electrical conductor.
 17. Themethod of claim 16, wherein preventing localized stresses comprisesubstantially reducing bending stresses.
 18. The method of claim 15,wherein twistably extending the portion comprises spreading stressesover the desired fatigue dissipation length.
 19. The method of claim 15,wherein routing the adjacent portions comprises preventing localizedstresses in the high voltage electrical conductor.
 20. The method ofclaim 19, wherein preventing localized stresses comprises eliminatingsharp angles in the high voltage electrical conductor.
 21. The method ofclaim 15, comprising selecting the desired fatigue dissipation lengthand the desired lengths and gradual curvatures to increase the cyclicallife of the high voltage electrical conductor associated with rotationalcycles of opening and closing the rotatable display relative to theportable computer housing.